1081. Rational Sum (20) PAT甲级

#include<stdio.h>
#include<math.h>
#include<algorithm>

using namespace std;

typedef long long ll;

ll gcd(ll a,ll b){
if(a%b==0)
return b;
else
return gcd(b,a%b);
}

struct Fraction{
ll up;
ll down;
};

Fraction reduction(Fraction result){
if(result.down<0){
result.up=-result.up;
result.down=-result.down;
}

if(result.up==0){
result.down=1;
}else{
int d=gcd(abs(result.down),abs(result.up));
//printf("%d\n",d);
result.down/=d;
result.up/=d;
}

//printf("%lld ",result.up);
//printf("%lld\n",result.down);
return result;
}

Fraction add(Fraction a,Fraction b){
Fraction result;
result.up=a.down*b.up+a.up*b.down;
result.down=a.down*b.down;
//printf("%lld ",result.up);
//printf("%lld\n",result.down);
return reduction(result);
}

void showResult(Fraction r){
r=reduction(r);
if(r.down==1)   printf("%lld\n",r.up);
else if(abs(r.up)>r.down)   printf("%lld %lld/%lld\n",r.up/r.down,abs(r.up)%r.down,r.down);
else    printf("%lld/%lld\n",r.up,r.down);
}

int main(){
int n;
scanf("%d",&n);
Fraction sum,temp;
sum.down=1;sum.up=0;

for(int i=0;i<n;i++){
scanf("%lld/%lld",&temp.up,&temp.down);
sum=add(sum,temp);
//showResult(sum);
}

showResult(sum);
return 0;
}